Rigid polyurethane/polyisocyanate foams containing paraffinic based oils

Abstract

The invention is a rigid polyurethane foam to which a base stock lubricating oil made of at least 55 weight percent paraffinic carbons and less than 10 weight percent aromatic carbons has been added as a hydrophobic agent protecting the polyurethane foam from reacting with environmental moisture. The foam is useful for deposit in railroad spike holes or any structural member having a cavity and where moisture within or on the cavity would otherwise react with the isocyanate to produce an uncontrollable foaming mass.

We claim: 
     
       1. A method of making a rigid polyurethane/polyisocyanurate foam in the presence of environmental water wherein the rigid polyurethane/polyisocyanurate foam has a density which does not vary by greater than 20 percent of the same rigid polyurethane/polyisocyanurate foam formed in the absence of environmental water, and wherein said rigid polyurethane/polyisocyanurate foam is made by reacting an aromatic polyisocyanate with a polyol composition comprising (a) one or more compounds having at least two isocyanate reactive hydrogens,   (b) a blowing agent comprising water, and   (c) optionally a polyurethane promoting catalyst, a surfactant, emulsifier, crosslinker, and/or a trimerization catalyst, in the presence of a lubricating oil comprising a base stock having based on the weight of the base stock, at least 55 weight percent carbon atoms in paraffinic form and no more than 10 weight percent carbon atoms in aromatic form.     
     
     
       2. The method of claim 1, wherein the base stock contains less than 7 weight percent carbon atoms in aromatic form, based on the weight of the base stock. 
     
     
       3. The method of claim 1, wherein the base stock has no more than 20 weight percent carbon atoms in naphthenic form based on the weight of the base stock. 
     
     
       4. The method of claim 1, wherein the base stock has a viscosity gravity constant of less than 0.85. 
     
     
       5. The method of claim 1, wherein the amount of said oil is from 20 weight percent to 35 weight percent based on the weight of said polyol composition. 
     
     
       6. The method of claim 1, wherein the blowing agent consists of water. 
     
     
       7. The method of claim 1, wherein the amount of water is from 0.01 to 1.0 weight percent based on the weight of the polyol composition. 
     
     
       8. The method of claim 1, wherein the foam has a density which does not vary by greater than 15 percent of the same foam formed in the absence of environmental water. 
     
     
       9. The method of claim 8, wherein the foam has a density which does not vary by greater than 5 percent of the same foam formed in the absence of environmental water.